BugMeNot will display a list of shared credentials (usernames and passwords) along with a Success Rate percentage. Success Rate:

If the free account has limitations, you can simply abandon it later without any impact on your main digital identity.

Shared accounts are quickly banned, blocked, or have their passwords changed by the original account owner or the site administrators once unusual activity is detected. You may have to try dozens of username/password combinations before finding one that works.

: Never provide your own personal information or credit card details when trying shared accounts.